On 07/09/12 16:13, Steve Holdoway wrote:
As you've been very helpful in the past, can I ask
the best way forward
in addressing this problem.
In an attempt to reduce spam delivery to a local charity mail server, I
to the sendmail config. It did help. However, it also blocked some
important clents as well...
barnardos.org.nz - sends via 122-56-8-123.cid.global-gateway.net.nz
logon.i.govt.nz - has no IP address
ecan.govt.nz - sends via onyx.crc.govt.nz which has no IP address
probably being the most important.
How do you address this problem. I'm certain they all must have been
TIA for all ideas
That list of unmatched/missing rdns is the just the tip of the iceberg -
especially with the government departments. Requiring reverse DNS is
something we attempted years ago but the amount of legitimate e-mail
that was blocked (especially a lot of those .govt.nz domains) meant it
didn't last longer than a whole day. Even though it's the other guys
doing it wrong it's hard to explain to customers that are quick to say
"it works for ISP X, why not you guys?" Indeed, the "proper"
would be to try and chase up those providers but it is hard to justify
Are you using greylisting? That still nets some good results still -
stripping out the low hanging fruit before being processed by
traditional spam filtering.
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